The 1815 eruption of Mount Tambora was the most powerful in human recorded history, with a Volcanic Explosivity Index (VEI) of 7. Although its eruption reached a violent climax on 10 April 1815, increased steaming and small phreatic eruptions occurred during the next six months to three years. Tanguy pointed out that there may have been additional victims on Bali and East Java because of famine and disease. Their estimate was 11,000 Oppenheimer wrote that there were at least 71,000 deaths in total. Reid has estimated that 100,000 people on Sumbawa, Bali, and other locations died from the direct and indirect effects of the eruption.
The 1883 eruption of Krakatoa (Indonesian: Krakatau ) in the Sunda Strait began on the afternoon of Sunday, 26 August 1883, and peaked on the late morning of Monday, 27 August 1883, when over 70% of the island of Krakatoa and its surrounding archipelago were destroyed as it collapsed into a caldera. At least 36,417 deaths are attributed to the eruption and the tsunamis it created.
The Dutch East Indies campaign of 1941–1942 was the conquest of the Dutch East Indies (present-day Indonesia) by forces from the Empire of Japan. Forces from the Allies attempted unsuccessfully to defend the islands. The East Indies were targeted by the Japanese for their rich oil resources which would become a vital asset during the war.
By 22 July 1966, the Malaysian Prime Minister Tunku Abdul Rahman estimated that there were approximately 700 Communists in Indonesian Kalimantan and about 2,000 sympathisers.
On 25 March 1969, Indonesian forces eliminated the Third Branch of the SPGF at Songkong in West Kalimantan following a two-day battle, wiping out the Sarawak People's Guerrilla Force's largest corps.
To replace the decimated SPGF, the Sarawak Communist Organisation created the North Kalimantan People's Guerrilla Force at Nonok on 13 July 1969.
On 30 March 1970, Wen Ming Chyuan, the Head of the Sarawak People's Guerrillas in Sarawak's First Division, formed the North Kalimantan Communist Party.
On 14 August 1997, the managed floating exchange regime was replaced by a free-floating exchange rate arrangement. The rupiah dropped further. The IMF came forward with a rescue package of $23 billion, but the rupiah was sinking further amid fears over corporate debts, massive selling of rupiah, and strong demand for dollars.
Airbus A300B4-220, Garuda Indonesia Flight 152, which departed from Jakarta, Indonesia, and was preparing to land at Medan, North Sumatra, crashed into mountainous terrain, killing 222 passengers and 12 crew members. The causes included turning left instead of right as instructed by the ATC and descending below the assigned altitude of 2,000 feet due to pilot error.
On 28 September 2018, a shallow, large earthquake struck in the neck of the Minahasa Peninsula, Indonesia, with its epicentre located in the mountainous Donggala Regency, Central Sulawesi. The magnitude 7.5 quake was located 70 km (43 mi) away from the provincial capital Palu and was felt as far away as Samarinda on East Kalimantan and also in Tawau, Malaysia. The combined effects of the earthquake and tsunami led to the deaths of an estimated 4,340 people.